Laser-Powered Aircraft Are The Future of Flight. Maybe

Aerospace engineer Leik Myrabo is absolutely sure lasers are the future of flight, and he’s confident we’ll be flying at hypersonic speed using beam-powered propulsion within a generation.

But experts doubt that.

Myrabo has spent two decades developing laser propulsion technology, which he laid out during "Expanding the Vision of Sustainable Mobility," a conference sponsored by the Art Center College of Design, one of the nation’s premier transportation design colleges.

Although it sounds like something out of Star Trek, Myrabo says the technology exists now and the challenge has shifted from sorting out the science to actually building the aircraft. He’s confident that challenge will be met within 20 years, ushering in a new era of flight.

"The whole philosophy behind my work is about doing much more with much less," Myrabo, a professor at Rensselaer Polytechnic Institute in New York, told Wired.com. "It’s about hypersonic transport for the period beyond oil. It’s about mass transit for the future."

Myrabo first got the idea in 1988 while working on the "Star Wars" anti-missile shield. He calls it LightCraft, a funnel-shaped craft with a parabolic reflector. It channels the heat generated by a laser into its center, heating the air to about 30,000 degrees and causing the it to explode, generating thrust. Small jets of pressurized nitrogen spin the LightCraft at 6,000 RPM to maintain stability.

It was all just theoretical research – which the U.S. Air Force, NASA and the Strategic Defense Initiative provided $600,000 to help finance – until 1997. That’s when Myrabo, working with the U.S. Army at the White Sands Missile Range in New Mexico, propelled a small LightCraft prototype (pictured at right with Tregenna Myrabo, business manager of Lightcraft Technologies; it was 6 inches long and weighed 2 ounces) 50 feet into the air. Another test in 2000 using a 10-kilowatt pulsed-carbon-dioxide laser saw the LightCraft climb to 233 feet during a 12.7-second flight. That’s not very high or very long, but then Robert Goddard’s first liquid-fueled rocket climbed just 41 feet during a 2.5-second flight.

Myrabo reportedly has made more than 140 test flights using small prototypes. He isn’t the only one exploring this field, either. Five years ago, NASA joined Tim Blackwell, a researcher at the Center for Applied Optics at the University of Alabama in Huntsville, in using laser propulsion to power a small model airplane. Researchers at the University of Tokyo have used a laser to propel a tiny airplane and detailed their findings in the journal Applied Physics Letters in 2002. Myrabo says he’s especially excited about tests being conducted cooperatively between the U.S. and Brazilian air forces; those tests, he says, are being done at greater power than any before.

Lasers remain the sticking point; even the most powerful laser is capable of only a modest test flight. But Myrabo is confident we’ll have that problem licked before long.

"In one generation, the science and technology needed to build and fly full-size LightCraft has been developed to maturity, ripe for commercialization," he writes in his forthcoming book, The LightCraft Handbook, slated for publication in April. "All that’s needed now is to actually build them. The problem has evolved from a scientific one to an engineering one."

"The propellant runs out before the LightCraft gets very far," Coyle said. "It’s sort of like trying to blow a paper airplane across the room with you own breath. You can give it a push with your first puff, but then the paper airplane is too far away and you can’t blow enough air to keep it going."

Nonetheless, Myrabo’s book lays out a broader vision for the technology, which he says in his book will bring "fringe benefits beyond access to space resources, space exploration and environmental preservation will also appear. Energy beamed down from power stations in space can be used for electrical propulsion of cars, trucks and trains, and for heating and cooling. Fossil fuel consumption and carbon dioxide generation will plummet. A global power system infrastructure with many parallel components, highly resistant to failure and sabotage, will emerge. The world will be a cleaner, safer place …"

Myrabo is almost dumbfounded that more people aren’t excited by laser-propelled flight, and he’s dismissive of jet technology. "You have a huge plane that has to lift 100,000 pounds of jet fuel off the ground," he says. "If you were able to offload all that fuel you wouldn’t need the wings. They’re just an unnecessary weight burden."

But jets will remain the dominant form of air travel for some time. Given the constraints of the technology, Myrabo says laser propulsion will be limited to launching satellites into low orbit — and even that is at least five or 10 years away. Still, he says the technology could reduce the cost of orbital flight by a factor of 1,000.

"There is nothing in chemical rocketry that can compete with that," he says.

He foresees laser flight carrying people around the globe and into space by 2020. Ground-based lasers called LightPorts would provide the energy needed to propel the crafts. It won’t become viable, he says, until the cost of jet fuel becomes so prohibitive the aviation industry embraces an alternative. Myrabo bases his timeline on the fact costs are moving in the right direction, with oil going up as lasers come down.

"Things have gotten to the point where you can buy the beaming power for a few dollars a watt," he says. "That’s when the whole thing becomes viable as a commercial enterprise."

At that point, he says, we could fly from New York to Tokyo in 45 minutes.

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